Monodispersed Eu₂O₃-Modified Fe₃O₄@NCG Composites as Highly Efficient and Ultra-stable Catalysts for Rechargeable Zn–Air Batteries

Abstract

Constructing highly efficient cathode catalysts for Zn–air batteries (ZABs) is an attractive research topic in sustainable energy storage area. Herein, the rare-earth metal oxide modification strategy has been proposed to construct the highly efficient and ultra-stable catalysts for ZABs. Accordingly, a graphene oxide-doped carbon-supported Eu2O3-modified Fe3O4 (Fe3O4/Eu2O3@NCG) catalyst is developed with layered Fe–Eu-MOF/GO as a precursor. Detailed characterization reveals that Fe3O4/Eu2O3@NCG possesses unique structural properties, including carbon–metal–carbon configuration, plentiful oxygen vacancies, and variable metal-active sites, which endows the catalyst with strong conductivity, high activity, and ultra-long stability. The optimal Fe3O4/Eu2O3@NCG catalyst exhibits an outstanding electrochemical performance, and the potential difference (E gap) between oxygen reduction reaction and oxygen evolution reaction is merely 0.68 V at 0.1 M KOH condition. Moreover, density functional theory calculations are employed to investigate the reaction mechanism and the synergetic effect between Fe and Eu atoms. Most importantly, the Fe3O4/Eu2O3@NCG-based aqueous ZAB delivers a high power density (218 mW/cm2), specific capacity (854 mA h/g@5 mA/cm2), and an impressive ultra-long cycle property with more than 1000 h (>6000 cycles) charge–discharge cycle life. In addition, the Fe3O4/Eu2O3@NCG-based all-solid-state ZAB also exhibits an outstanding performance, achieving >460 h cycle life (>2760 cycles) and strong practical application capability.

Flexible Solid‐State Metal‐Air Batteries: The Booming of Portable Energy Supplies

“…[51] In addition to cobalt, iron is also a promising candidate as the anode catalyst. FeÀ S, [52] FeÀ O, [30,53] and especially FeÀ N [31][32][33]54] motifs exhibit excellent ORR and decent OER activities. For example, Yang et.…”

Toward Self‐Supported Bifunctional Air Electrodes for Flexible Solid‐State Zn–Air Batteries

“…On the other hand, the rare-earth metal oxide modification strategy has been applied to construct highly efficient and ultrastable electrodes for FSZABs. [79] Hence, an Fe 3 O 4 /Eu 2 O 3 @NCG (denoting GO-doped carbon layer as NCG) electrode was synthesized by employing layered Fe-Eu MOF/GO (Fe-Eu-MOF/GO) as a precursor (Figure 12a). A solid-state ZAB based on such a [63] Copyright 2018, Wiley-VCH.…”

“…In addition, the density of the state value was larger, suggesting a fast electron transfer rate. [79] Moreover, layered double hydroxides (LDHs) usually display superior OER activity due to their large interlayer spacing for mass transport to promote the oxygen reaction. Consequently, combining LDHs with transition metal oxides to construct self-supported bifunctional composite air electrodes is an attractive approach.…”

“…Here, we listed a few common synthesis strategies for preparing self-supported air electrodes, which include pyrolysis, hydrothermal/solvothermal, electrospinning techniques, vapor deposition, and combination of these methods. [79] Copyright 2022, American Chemical Society. g) Schematic illustration of the synthesis process of NiCo 2 O 4 @NiMn LDH on Ni foam.…”

“…Such air electrodes can also be prepared via pyrolysis, where MOFs, ZIFs, and COFs materials are often used as pyrolysis precursors. [36,79] The performances of pyrolysis-made single-atom metal or alloy catalysts/substrates, such as Co-N x /C/Ti, CoNi alloy NCNSAs/CC, and SAFe-SWCNT [57] were explored recently. The tight contact between the catalysts and conducting substrates can facilitate electron transfer and improve the dispersion of the catalyst, thus facilitating the reaction process.…”